When a medical device such as hearing prosthesis is implanted in a human recipient, there is generally a need to configure the device with one or more operational settings to help ensure comfortable use of the device by the recipient. Further, as the device is used over time, there may be a need to recalibrate or adjust configuration of the device, to help ensure continued comfortable use.
A typical hearing prosthesis, for example, functions to receive auditory signals and to correspondingly stimulate the recipient's hearing system, for instance by aiding in conduction of sound waves to or through the ear canal or middle ear, or by directly or indirectly stimulating the recipient's auditory nerve or brain stem. In practice, such a prosthesis may thus be programmed or otherwise arranged to map between various levels of received auditory signals and corresponding levels of stimulation to be applied.
One of the operational parameters or settings of such a prosthesis is a maximum comfort level, or “C-level”, which defines the maximum allowable level of stimulation that does not produce an uncomfortable loudness sensation for the recipient. Ideally, the C-level should be set to a level that is high enough to allow adequate stimulation to the recipient but to avoid overstimulation and possibly resulting pain or injury to the recipient.
In general, the C-level for a given prosthesis may vary from person to person and must therefore be individually set for a person after implantation of the prosthesis. Conventionally, this “fitting” or configuration process is manually carried out by an audiologist, clinician, or other healthcare professional, by applying stimulation pulses and then receiving an indication from the recipient as to the hearing perception and the level of comfort of the resulting sound.
Unfortunately, however, this fitting process is typically quite time consuming. Further, in locations where there is a lack of adequate audiological infrastructure and/or trained clinicians, a hearing prosthesis may not be optimally fitted for each particular recipient. Moreover, since this fitting procedure relies on subjective measurements, children and pre-lingually deaf or congenitally deaf patients are often unable to provide an adequate impression of the hearing sensation resulting from the stimulation test pulses. This further complicates the process, potentially resulting in poor fitting of the prosthesis.
Yet further, it would be desirable to provide a mechanism to perform this fitting process during or immediately after surgical implantation of the prosthesis, to help ensure that the implant is performing properly before closing up the patient. Again in this scenario, however, it may be impossible to obtain subjective feedback from the recipient.